DESCRIPTION: This application proposes the further advancement of a highly precise low cost electrical cutting instrument based on pulsed plasma-mediated discharges in a liquid medium. Applications include traction-free removal of vitreoretinal membranes to avoid the risk of mechanical damage to the underlying retina associated with forces exerted by mechanical instruments. This device will also be applied for capsulotomy with no risk of rupture and mechanical stress to zonular fibers exerted during capsulorhexis. Additionally, capsulotomies will be created simply in eyes with poor visualization of the capsule, or with a miotic pupil. Applications to non-penetrating trabeculectomy and other ophthalmic and non-ophthalmic microsurgical procedures will be explored. This device also has coagulation, electro-adhesion and injection operating capabilities. During the last two years they have developed a device called Pulsed Electron Avalanche Knife (PEAK) for cutting soft tissue with 100 ns-long pulses of high voltage applied via a pointed electrode. This instrument was capable of precise dissection of soft tissue in liquid media, but certain limitations were found due to the following factors: (1) Individual pulses produce a series of perforations, which did not always merge into a continuous cut. (2) Depth and width of the cut were linked due to spherical geometry of cavitation bubbles. (3) The instrument did not dissect more fibrotic tissue such as sclera and cornea. (4) Pointed microelectrodes were not able to coagulate tissue. A much more advanced version of the instrument is presented in this proposal, which overcomes those previous limitations by (1) Application of an elongated electrode dissecting tissue with its cutting edges rather than with its apex; (2) Applying a burst of pulses instead of a single sub-microsecond pulse thus avoiding strong cavitation (3) Changing the mechanism of interaction from mechanical fragmentation to rapid vaporization and ionization will extend applicability to fibrous tissues; (4) A coagulation capability that can be achieved due to sufficiently large exposed area of elongated electrode. Implementation of the described proposal should result in creation of the most precise and broadly-applicable tractionless surgical device that will not only strongly improve precision and safety of the current surgical procedures but may lead to development of new microsurgical techniques. This device, allowing for "cold" dissection, coagulation, electro-adhesive manipulation of tissue and microinjection will also include illumination, irrigation and suction. It is miniaturizable to a 25 gauge size and can be incorporated into an endoscope. The low cost and small size of this system combined with high precision, reliability and versatility should allow for a widespread acceptance into operating practice.